HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Regular Issue
Vol. 34, No. 11, 1992
Published online:
■ Novel Natural Colorants from Monascus anka U-1
Kyoko Sato, Satoshi Iwakami, Yukihiro Goda, Emi Okuyama, Kunitoshi Yoshihira, Takahiko Ichi, Yoshinobu Odake, Hiroshi Noguchi,* and Ushio Sankawa
*Faculty of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan
Abstract
The structure of xanthomonasin A(C21H24O7), a natural colorant with a novel carbon skeleton (furanoisophthalide), produced by a mutant strain of Monascus anka, has been determined by the application of INADEQUATE experiment as well as by the variety of correlation spectroscopic techniques.
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■ A Facile Synthesis of Highly Functionalized Unsymmetrical Heterobiaryls Utilizing the Intramolecular Ullmann Coupling Reaction Directed by Salicyl Alcohol as a Template
Masami Takahashi, Tooru Kurada, Tsuyoshi Ogiku, Hiroshi Ohmizu, Kazuhiko Kondo, and Tameo Iwasaki*
*Department of Synthetic Chemistry, Research Laboratory of Applied Biochemistry, Tanabe Seiyaku Co., Ltd., 16-89 Kashima, Yodogawa, Osaka 532, Japan
Abstract
Heterobiaryls (4) were synthesized in good yields utilizing the intramolecular Ullmann coupling reaction directed by salicyl alcohol as a template. The regioselective cleavage of the two ester bonds of 4 gave the highly functionalized unsymmetrical heterobiaryls having substituents which are incompatible with organometallic reagents.
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■ Syntheses of 3,8-Dihydroxyimidazo[1,2-a]pyridines and [1,2-a]pyrazines
Muriel Doise, Dominique Blondeau, and Henri Sliwa*
*Laboratoire de Chimie Organique et Environnement, Université des Sciences et Technologies de Lille, 59655 Villeneuve d’ Ascq Cedex, France
Abstract
3,8-Dihydroxyimidazo[1,2-a]pyridines and [1,2-a]pyrazines were prepared by condensation of glyoxal derivatives with methyl or benzyl ethers of 2-amino-3-hydroxypyridine and pyrazine followed by cleavage of the ether group.
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■ Syntheses of Functionalized N-(2-Pyridyl)-α-amino Acids and Esters by Ring Opening of Imidazo[1,2-a]pyridine
Muriel Doise, Dominique Blondeau, and Henri Sliwa*
*Laboratoire de Chimie Organique et Environnement, Université des Sciences et Technologies de Lille, 59655 Villeneuve d’ Ascq Cedex, France
Abstract
This report is devoted to the ring opening of the imidazole nucleus of functionalized imidazo[1,2-a]pyridines, by methanol in strong acid medium (HClO4) leading to esters of N-(2-pyridyl)-α-amino acids in which the heterocyclic moiety bears a functional group. Direct obtention of this kind of compounds could be achieved by condensation of glyoxal derivatives with ethers of 2-amino-3-hydroxypyridine or with 2-amino-3(or 5)-nitropyridine in methanolic perchloric acid.
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■ Approaches to the Generation of 2,3-Indolyne
Samuel C. Conway and Gordon W. Gribble*
*Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, U.S.A.
Abstract
Several unsuccessful attempts to generate and trap 1-phenylsulfonyl-2,3-indolyne (4) from 2-lithio-3-bromo-1-phenylsulfonylindole (9) and 2-lithio-3-iodo-1-phenylsulfonylindole (12), generated by different methods, are described. The remarkable stability of 9 and 12 towards elimination parallels previous observations involving the stability of 2-lithio-3-bromobenzo[b]furan and other ortho-metalated halogenated five-membered ring heterocycles.
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■ GifIV Oxidation of Some Indolic Alkaloids*
Farès A. Farès and Christopher K. Jankowski*
*Départment de chimie, Université de Moncton, Moncton, N. B., Canada
Abstract
The title oxidation was performed on four indolic alkaloids, β-carboline (1), reserpine (6), ajmaline (10) and ibogaine (11), leading to alicyclic hydroxylation of the starting materials. The numerous side products characterised during this reaction (due to reduction or coupling with solvent) as well as selective deuterium labelling experiments enabled us apart from the oxidation sites to study the Gif reaction mechanism.
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■ Facile Stereospecific Synthesis of α-Anomeric 2’-Deoxynucleosides
Kazuo Shinozuka,* Yoshiki Hirota, Tsutomu Morita, and Hiroaki Sawai
*Department of Chemistry, Faculty of Engineering, Gunma University, Tenjincho, Kiryu City 376, Japan
Abstract
The coupling reaction of activated nucleobases, such as the sodium salts of N-benzoyladenine and 6-chloropurine and 2,4-bis-O-trimethylsilylthymine, with 1-α-chloro-2-deoxy-3,5-di-O-p-toluoylribofuranose (1) in a mixture of acetonitrile and tetrahydrofuran leads to the stereospecific formation of α-anomeric 2’-deoxynucleosides with satisfactory yields. The ratio of the distribution between the resulted α- and β-stereoisomers was about 3:1 in each case. The method is simple and applicable to the preparation of both purine and pyrimidine α-2’-deoxynucleosides.
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■ New Acridone Alkaloids from Citrus Plants
Yuko Takemura, Hiromi Uchida, Motoharu Ju-ichi,* Mitsuo Omura, Chihiro Ito, Kiyomi Nakagawa, Tomohisa Ono, and Hiroshi Furukawa
*Faculty of Pharmaceutical Sciences, Mukogawa Women’s University, Nishinomiya, Hyogo 663, Japan
Abstract
The spectroscopic structure elucidations of five new acridone alkaloids named yukocitrine (1), yukodine (3), yukodinine (4), grandisine-III (6) and pummeline (7) from some Citrus plants were described.
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■ C-Nucleosides. 20. Ring Transformation of 5-Hydroxy-5-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)furan-2(5H)-one with 2-Aminothiophenol and 2-Aminoethanethiol to 1,5-Benzothiazepine and 1,4-Thiazine
Yasutaka Ito, Masakazu Wakimura, Chihiro Ito, and Isamu Maeba*
*Faculty of Pharmacy, Meijo University, Tempaku-ku, Nagoya 468, Japan
Abstract
Treatment of 1 with 2-aminothiophenol afforded 2-[1-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)carbonyl]-2,3-dihydro-1,5-benzothiazepin-4(5H)-one (2). Dehydrogenation of 2 with 2,3-dichloro-5,6-dicyano-p-benzoquinone and a trace amount of p-toluenesulfonic acid in benzene afforded 2-[1-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)carbonyl]-1,5-benzothiazepin-4(5H)-one (3). The removal of the sugar protecting groups in 3 afforded 2-[1-(1,4-anhydro-2-deoxy-D-erythro-pent-1-enofuranosyl)carbonyl]-1,5-benzothiazepin-4(5H)-one (4) resulting from the abstruction by base of H-1’. Compound (1) was treated with 2-aminoethanethiol to give 3-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)-5,6-dihydro-4H-1,4-thiazine-2-carboxaldehyde (5). Deprotection of the compound (5) with aqueous sodium carbonate afforded the deprotected compound (6).
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■ New and Efficient Syntheses of 4-Carbamoylquinuclidine
Takeo Kanai, Seiichiro Nomoto, Yuhki Komatsu, and Katsuyuki Ogura*
*Graduate School of Science and Technology, Chiba University, 1-33 Yayoicho, Inageku, Chiba 263, Japan
Abstract
Two efficent routes starting from 4-carbamoylpiperidine or 2,2’,2"-trichlorotriethylamine were developed for preparing 4-cyanoquinuclidine which was hydrolyzed to give 4-carbamoylquinuclidine, a chemical modifier of cephalosporin antibiotics.
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■ Recent Advances in the Synthesis of Antibacterial Quinolones
Stanislav Radl* and Daniel Bouzard
*Hoffmann-La Roche, Inc., 340 Kingsland Street, Nutley, N. J. 07110, U.S.A.
Abstract
This review surveys the main synthetic approaches used for the construction of antibacterial quinolones, including aza analogs (naphthyridones, cinnolones) and condensed polycyclic analogs, with an emphasis on the more versatile methods which are potentially useful in other fields of heterocyclic chemistry. Simpler non-condensed monocyclic analogs, i.e., pyridone and pyridainone carboxylic acids are also briefly mentioned.
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■ Mechanisms and Rates of the Electrophilic Substitution Reactions of Heterocycles
Alan R. Katritzky* and Wei-Qiang Fan
*Department of Chemistry, University of Florida, Gainesville, FL 32611, U.S.A.
Abstract
The mechanisms and rates of electrophilic substitution reactions, especially acid catalyzed hydrogen exchange and nitration, of heterocycles are discussed.